Internal-combustion engine.



PATENTED NOV. 19. 1907.

A. ROLLASON.

INTERNAL COMBUSTION ENGINE.

APPLICATION FILED MAY 2. 1907.

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INVEN'IOR WITNESSES ARTHUR ROLLASON, OF LONG EATON, ENGLAND.

INTERNAL COMBUSTION ENGINE.

Specification of Letters Patent;

Patented Nov. 19, 1907.

Application filed May 2. 1907. Serial No. 371,620.

To all whom it may concern:

Be it known that I, ARTHUR RoLLAsoN, a subject ofthe King of Great Britain, residing at Long Eaton, in the county of Derby, England, engineer, have invented certain-new and useful Improvements in Internal-Oombustion Engines, of which the following'is a specification. V

This inventionrelates to internal combustion engines using liquid fuel and has for its object to increase the elficiency and economy of such engines, and this it effects by a particularconstruc'tion hereinafter described in which the scavenging or cooling charge of air left in the clearance space of the cylinder at the end of the scavenging stroke is in part containedin the space immediately in rear of the piston and in part in a space communicating freely therewith but out of line with the cylinder. The former pal't-of the cool air charge is o posed to the entering charge of vaporized el or combustible mixture drawn in through the inlet valve in the cylinder end on the suction or charging stroke and serves to break up the entering charge of combustible and, promote its diffusion, while the other portion of the cool air charge which, being out of the ath of the entering charge, does not mix t erewith, or mixes only to a comparatively small extent, during the suction and com ression strokes, will u on ignition of the 0 large absorb heat at t e beginning of the explosion, thus reducing the temperature of ex losion and the initial pressure in the c lin er and reventing excessive shock to t e engine, t e heat so absorbed being, however, returned to the working fluid during the expansion stroke.

In the preferred construction the additional scavenging air valve and the exhaust valve are placed in theside chambenof the clearance space and referably op osite to each other, so that t e entering c arge of cool air im inges directly on the exhaust valve, and a l the valves as well as the cylinder are preferably jacketed.

The arrangement above described has proved itself a simple and effective construction whereby (1) the cylinder may be scavenged by diluting the combustion products left in the clearance space after the previous exhaust stroke and expelling the greater part thereof, (2) overheating of the cylinder,

piston and valves, and premature ignition of into the cylinder on the suction stroke, and t) theshock at explosion diminished and a lugher average pressure obtained during the expansion stroke by' means of the diluting charge of cool air. In a six stroke cycle englne the additional scavenging valve is opened during the two strokes made by the engine between the exhaust and suction strokes to admit a full charge of cold air which cools the cylinder, piston head and exhaust valve and when expelled carries with it the combustion products leftin the cylinder clearance at the end of the exhaust stroke, leaving the clearance space filled with comparatively cool and pure air.

The cooling of the cylinder and also the presence of the comparatively cool air therein during the suction stroke insteadiof hot products of combustion not only prevents premature ignition of the charge but also enables a greater mass of combustible mixture to be drawn in during the suction stroke since owing to the low temperature of the cylinder and its contents there will be little if any, expansion of the combustible charge as 1t 1s drawn into the cylinder on the SUCtlOll' stroke, and there may even be an absolute reduction .in its temperature and corresponding increase in its density, as for example when the liquid fuel used is petroleum and the temperature at which the charge is delivered by the carburetor is greater than that of the cylinder and its contents at the time of introduction of the charge. Further, the presence of the residual air in the clearance space of the cylinder enables a richer oombustible mixture to be used than would ;be possible without imperfect combustion were there no residual air or only waste combustionproducts in the cylinder at the beginning of the suction stroke.

The accompanying drawing represents a longitudinal section of a six stroke cycle onine constructed according to the present invention portions being broken away so as to avoid confusion.

In this drawing A is the admission valve, B a scavenging valve, C the exhaust valve, D a lay shaft operating the valve spindles A, 'B, C, by means of cams and making one revolution for every three of the crank shaft E.

Assuming that the piston F in the-position the combustion chamber will be filled with hot products of.

combustion at atmospheric pressure. On the next forward stroke the valve B is opened by means of a lever indicated at L which depresses. spindle B',-a1ld which'is operated bylinks actuated by a.

'cam B on shaftD, and said valve is held opened until the end of the-return stroke, so that the pistonwill then have drawn in and discharged through the valve B and port G- a quantity-"of cold air thereby cooling the-exs -Felts; chamber and; leaving at iatterfilled-with air at; a comparativelylow. temperature, and

. --comparativel free from; exhaust gases and other residua products of the previous workfAt 'thebeginning of the next for:

the valve A is opened by a lever a ca e on shaft D, "said-valve is hel opened thereby 'until .t e completion of? the forward stroke durin mixture will der through the valve A and the port I which communicates with a vaporizer. The charge as it is drawn in encounters and mixes with the air inthat part of the clearancespace immediately behind the piston head. The charge is compressed on the return stroke, 18 ignited by suitablemeans at the end of the stroke, and expanding drives the' piston forward, the exhaust gases being eX- pelled operating on spindle C' andjport J on the sixth stroke of the engine during which the exhaust valve is held open by the cam shaft.

reducin piston head, and combustion;

which a charge of combustible." avebeen drawn into the cylinname to p I two subscribing witnesses. through the'valve C opened by cam C v Since the into, which t e valves 13, 0, open is situated -to one side of the cylinder and out of the line of the piston and of the incoming charge, the

cool, air in this spaceat the beginning of the charging stroke willnot be intimately mixed with thec'harge, but actsas a diluting charge by the a sorption of heat and iving a higher mean pressure during the wor 'n'g' stroke by returning the heat so absorbed to the work ing' fluidand also by insuring complete conibustion of the-combustible. v

Having thus described the-nature of this invention and the best means I know of carrying the ,same into practical eii'ect, I

claim.:

;- a 1. 1nv a six-stroke cycle internal combustionengine having an additional scavenging valve, a combustion chamber or clearance space having lpart thereof placed towards one side of the cy ind er out of line with the piston and inlet valve, substantially as described. 2. Ina six-stroke cycle engine such as referred to in the preceding claim, a clearance space placed toone side of the cylinder and havingthe exhaust valve and an additional scavenging-valve oppositely'disposed therein,

substanti y as described.

lntestlmony whereof I have signed my this specification in the presence of ARTHUR ROLLA-SON.

Witnesses:

JOSEPH WILLARD, .W. J. SKEBTEN'.

part of the combustion chamber the initial pressure of the explosion I 

